As a magnet body for field pole to be arranged in a rotating electric machine, a magnet body for field pole formed by cutting a plate shape magnet body (hereinafter, simply referred to as the “magnet body”) into a plurality of magnet pieces and bonding the plurality of magnet pieces to each other is conventionally known. Since such a magnet body for field pole is formed by the plurality of magnet pieces, the volume of an individual magnet piece can be reduced, so that an overcurrent generated in the magnet piece by a change in a magnetic field due to rotation of a rotor can be reduced. Thereby, heat generation of the magnet body for field pole following the generation of the overcurrent is suppressed, so that irreversible thermal demagnetization can be prevented.
JP2009-142081A discloses that by mounting a magnet body in which cutouts are provided along cutting planned lines onto a die supporting the magnet body in both end parts in the direction perpendicular to the cutting planned lines and squeezing in upper parts of the cutting planned lines downward by a blade, the magnet body is cut along the cutting planned lines and a plurality of magnet pieces is manufactured.
The magnet body is fed in the longitudinal direction on the die, and a leading end part in the feeding direction is successively cut by the blade one by one. The magnet body is cut by squeezing in the blade downward from the upper parts of the cutting planned lines in a state where the magnet body is supported by the die on both sides of the cutting planned lines. That is, the magnet body is cut by three-point bending.
Since the magnet body is susceptible to rust, a surface of the magnet body is coated with a material having an anti-rust effect. This coating film material is a ductile material. Thus, there is sometimes a case where at the time of cutting the magnet body, the coating film is not drawn out enough to be cut in parts of the cutting planned lines, so that the coating film is not cut. In a case where the coating film is not cut, the cut magnet piece and the pre-cut magnet body are coupled to each other by the coating film. As a result, a disadvantage that at the time of conveying the cut magnet piece to the following step, the pre-cut magnet body is conveyed at the same time is subsequently generated.